This invention relates to the determination of the quantity of a component in material and has particular relationship to the determination of the quantity of uranium in material. In the interest of facilitating the understanding of this invention, this application deals predominately with the determination of the quantity of uranium in a uranium solution. To the extent this invention is applicable to quantity determinations of other types such determinations are regarded as within the scope of this invention.
There is being developed a solution mining technique for extracting uranium directly from ore without removing the ore from the ground. This technique obviates the need for tunneling and/or excavation and thus has low operating and land reclamation costs. Typically, in this process an inexpensive, innocuous solvent is pumped into the ground through wells that penetrate the ore body. The solution dissolves and removes the compounds of uranium as it is drawn through the porous ore, which is typically sandstone, by pumps at the heads of other wells that pass through the ore body. The uranium-bearing solution is processed at a plant using ion exchange techniques. The usual ore handling and crushing steps are thereby circumvented. It is contemplated that the uranium solutions will typically contain concentrations from 10 to 1000 ppm (parts per million) and will flow at rates from 10 to 300 gal/min. It is anticipated that a processing plant will simultaneously handle solution from more than one well or group of wells and a monitoring system is needed for each input to record the rate and total quantity of uranium delivered. This information serves (i) to monitor the performance of the wells, (ii) to determine the royalty payment due each well owner, and (iii) to adjust the processes at the extraction plant. So that the data derived by the monitoring will serve these purposes, it is necessary that the separate uranium-solution flow lines be monitored separately with samples periodically drawn from the solutions during operation. There may be as many as 20 of such flow lines in one installation.
It is an object of this invention to provide apparatus for, and a method of, detecting the quantity of uranium in the solutions. This method and apparatus measures the concentration of uranium in solution, which together with the solution's flow rate, specifies the total quantity of uranium transported.
In accordance with the teachings of the prior art, the quantity of uranium is monitored by periodic chemical analysis of samples of the solution. This procedure is costly and cumbersome. In addition, the analysis may not lead to accurate and reliable results particularly, as may happen often, the composition of the solutions varies widely so that the chemical analysis does not yield a reliable representation of the uranium content of the solutions.
It is an object of this invention to overcome the disadvantages and drawbacks of the prior art and to provide a method and apparatus for reliably and accurately monitoring the uranium content of solutions and, more generally, such content of any material. It is also an object of this invention to provide such a method and apparatus which shall lend itself to continuous monitoring of material to measure its content of uranium.